The use of bind runes is ancient, probably arising almost simultaneously with the use of runes as an alphabet.
Essentially, a bind rune is a symbol composed of several runes, overlaid, one upon another, to form a single character. This is believed to concentrate the power of individual runes into a more potent force.
Carved into stones and used for sign posts or ancient posters! Your teenager's bedroom would have been a bit overcrowded with rocks in those days.